Air-brake apparatus.



H. M. P. MURPHY. AIR BRAKE APPARATUS, APPLICATION FILED APE.4, 1908.

- Patented Feb. 16, 1909 3 BHEETS+SHEBT 1 I INVENTOR J; m, 2%-

. Alforney H. MQP'. MURPHY.

AIR BRAl iE APPARATUS. APPLICATION FILED APR.4, 1908.

912,715.. Patented Feb. 16, 1909.

3 SHEETS-SHBET 2.

, z Atlarnzv H. M. P. MURPHY. AIR BRAKE APPARATUS. APPLIOATION FILEIj APEA, 1908.

91 2,7 1 5 Patented Feb. 16, 1909.

3 SHBETS-SHEET 3.

. WITNESSES INVENTOR.

UNITED STATES; PATENT ()FFICE.

H OWARDM. P. MURPHY, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR OF ONE-FOURTH TO .I. H. BOWMAN, OF MUNHALL, PENNSYLVANIA, AND ONE-EIGHTH TO JOSEPH M.

v NERY, OF PITTSBURG, PENNSYLVANIA.

AIR-BRAKE APPARATUS.

. Specification of Letters Patent.

Patented Feb. 1c, 1909'.

Application filed April 4, 1908. Serial No. 425,194.

invention being-to provide simpleand efficient means for controlling the operation of the'brakes under any and all of the conditions which arise.

; A further object-is to so construct a triple valvemecbanism that. it shall be-very sensitive to variationsof train pipe pressure, regardless of the length ofthe train onxwhich my improvements'may be employed.

- A further object is-to' improve in other re spects, the construction of triple valve mechanism to enhance the efficiencyof the same. Aff'urther object is traso construct a triple valve mechanism that; the maintenance of brake cylinder pressure will be insured when the brakes are. fully applied, notwithstand ing any leaks which might occur.

- A. further obiect is to embody in a triple valve mechanism, quick action and quick service features and to so construct the mechanism as to provide for various rates of release of'the brakes and recharge of the auxiliary reservoir. With-these objects in view, the invention consists in certain novel features of con struction and combinations and arrangementsbf parts as hereinafter set forth and pointed out in the claims.

In theeaccompanying drawings; Figure 1 is a sectional view. of. a triple valve mechanism embodying my improvements, the parts being shown in their normal reclzarge'and free release position; Fig. 2 is a view showing the valve devicesin restricted recharge the 'Iy'alve devices when in and restricted release? position; Fig.- 3 is a similar-flew with the parts in quick service position; Fig. 4 shows the positions of 'q'ui'ckservice lap position; Fig. 5 illustrates the full service posit'ion of the valve devices; .Fig. 6'is a view-showingthe full service lap? posi-' tion; Fig. 7 shows the position of tne'valve evices when theyassume their equalizatron lap and mamtaming? positiontFig. 8

shows the parts. in emer enc position;

Fig. 9- shows emergency ap .pos itionof the valve devices; Fig. .10 1s top plan view of the gradu'ating'valve; Fi ll-is a top plan view' of the main valve, an .Fig. 12 is. a plan View ofthe seat for the main valve.

- 1 represents a casing which may be secured to the end of anauxiliaryreservoir 2 so that the latter will forina head for one end of the casing, or the latter may, if desired be provided with a separate head" which m'ay,,in turn be secured to any convenient support and provided with suitable ducts ano assages. Y

ushing 3 is pressed into the casing 1 and the lower ortion of this bushing-constitutes a seat for a main slide valve D which movable longitudinally within the bushing, by means of the rod F of a piston G, the latter being movable within a chamber or cylinder G between one end of the bushing 3 and the opposite head of the easing adjacent to the auxiliary reservoir. For reasons which will hereinafter become apparent, motion should not. be transmitted a certain amount of lost motion between said piston rod and the valve. For this reason, the rod'F is provided "with two shoulders F F for engaging the valve at respective ends thereof, and these shoulders are so spaced apart that the rod can move a certain distance in one direction or the other before engaging the valve.

The rod F is recessed between its ends for the reception of a secondary or graduating valve E which has a close fit within said recess so that it will partake of the movementsof the rod through the full travel of the latter, and this secondary or graduating valveis pressed toward its seat on the main valve D, by'means of a light spring 1*.

Provision is made at Y for the attachment of the train ipe andthis inlet communicates with a, duct over the'bushing 3,.tl1c interior of which latterconstitutes the valve chamber R and the duct S is connected with this valve"v chamber through the medium of a duct R, anda portf in the valve seat X. A

* to the valve D throughout the full'travel of. the piston G and its rod, but thereshould be check valve R is located at the intersection of the ducts R and S, said check valve being so dis )osed. as to prevent a passage of train pipe uid from the duct S to duct R, but permitting a passage of fluid, under certain conditions, from the valve chamber R through the port f, and ducts R and S to the train pipe. The train pi e duct S also communicates with a large uct T and at the juncture of these ducts a check C is located and pressed upon its seat by a light spring 0, and so disposed as to prevent a passage of fluid through the duct T in the direction of the duct S. The check valve 0 is provided with a small duct g w ich operates to premit a restricted flow of train pipe fluid from the duct S to the duct, T, under certain conditions, when the pressure of the train pipe fluid is such as to raise the check valve an insufficient distance to fully open communication between the ports S and T. The valve 0 (as will hereinafter become apparent) therefore acts as an excess pressure valve at certain times. The purpose of thus providing fora restricted passage oftrain pipe fluid to the chamber with which the duct T communicates will be hereinafter explained. The duct '1 communicates with the valve chamber R and, through the forward portion of the latter, with the piston chamber G.

A duct 4 leads to the brake cylinder and this duct communicates with a duct V which latter communicates with a duct U terminating under a port I) in the valve seat X so that in certain positions of the valve D as hereinafterexplaine-d, brake cylinder air may be exhausted through a duct (1 in the casing 1, and so that sup ly fluid may also be admitted to the brane cylinder in certain other positions of the valve.

A duct V communicates at one end with a large porta in the valve seat X and at the other end with the duct V for the passage of fluid (as controlled by the valves) fromthe train pi e and fromthe auxiliary reservoir to the rake cylinder, and in the duct V acheck vlave B (heldto its seat by a light valve B) is located, so as to prevent braize cylinder fluid from entering the said duct,

from the duct V. The main slide valve seat X, contains also a port d communicating with the atmosphere through the duct d, which latter may, if desired. be connected by a suitable pipe, with a retaining valve. The valve seat Is. also contains a port 0 which is connected by means of a duct 0 with a large duct W, the latter communicating at one end with the auxiliary reservoir Z'and with the chamber G at the right of the piston in the latter. 1

The rod F is adapted to contain, in addition to the spring 1" hereinbefore referred to, two other springs N and N The spring i is of moderate strength and operates to normally hold a rod H in the position shown in atmospheric pressure in order to permit pressure in the chamber It to hold the valve E to its seat against pressure under and Fig. 1. The spring N presses, at one end against the bottom of its socket in the rod F, while its other end bears against the head H of a rod H, which latter projects beyond the piston G and is adapted to engage an abutment atthe auxiliary reservoir end of the chamber G The main valve D contains a cavity m for establishing communication under certain conditions between the exhaust port (Z and the port I), and this cavity perforinsiio other functions at any time except to cause the vlave D to be pressed firmly on its seat by the fluid pressure above it. The valve D also has a port h which, undercertain conditions, communicates with the port a in the seat X. In addition totlie ports and passages hereinbefore mentioned, the valve D is provided with a port K and a smaller port Z, the former being adaptedto register (under certain conditions) with the port I) in the seat X, and the port 1 being made to register in certain positions. of the valves, with the port a in the valve seat. The secondary or graduating valve E contains a cavity p for connecting the ports h and 7c undercertain conditions but at no t iniie to form any other connections. The valve E is disposed so as to permit of the uncovering and closing or the port Z and also to close communication between the ports h and it by forming a cover for these ports. inspection of the several views of the drawings illustratin different positions of. the valve, that the ports h and 7c are never uncovered by the graduating valve E.

The valve D is provided near its .right hand end with a large port Z and the graduating valve E is provided with an extension Z having a small port Z to become disposed over the port Z for controllin under certain 7 conditions, the passage oi iiuid from the chamber G at the left of piston G, to the brake cylinders through the port a and the ducts which connect the latter with the brake cylinders.

In order to permit the passage of fluid from the chamber G at the left of piston G, to the port Z when the valves assume the positions shown inFig. 3, the graduating valve E is providedwith a cavity Z and a port P. A cavity p in the valve it and a duct p in the valve D serve to provide means "for exposing a portion of the face of the valve E to tile valve from the auxiliary port c. The wall or lining of the chamber or cylinder G is provided at its left hand end with compara- It will be observed from an 1 tively large grooves forming ducts L L for the purpose of permitting, (when the piston G is at this end of the chamber G a flow of air around said piston. A large duct or passage Q in the end of the bushing 3 will per- A duct M is located in the wall or lining of the chamber or -cyfinder G: at the right hand end thereof. This duct varies in is of greater capacity than the passage M The, duct M, variously proportioned as above explained, constitutes a. by-pas's around the piston G under certainconditions and'for purposes whichwill be hereinafter fully explained. It will be observed that when the piston G occupies a position near the right end of the chamber G the duct M rovides means for admitting train chamber B through past the check valve left of the chamber pipe-fluid to that portion of the chamber G: to the right of piston G, from which the auxi'iary reservoir is charged through the duct W which connects the chamber G to the right of piston G Withthe auxiliary reservoir 2 as before explained.

It is apparent from an inspection of the drawings t at fluid can pass from the valve ort f and duct R, 2 to the train i e duct when the port f is not covere l y the main valve D as shown in Figs. 1 to 6,'

but that train pipe fluid can never enter the valve chamber it through this path, being revented -from so doing by the check valve .It will also be observed that Y the passage of. fluid from the valve chamber R to the train pipe duct S, will be prevented when the parts assume the positions shown in Figs. 7, 8 and 9, because the portf will .then be closed by the main valve D. The

main'valve, in its movements to the posi tions shown in'Figs. 7,'=8 and 9, will always gperate to close the port overingthe. port a whic communicates with the-brakecyinder ducts.

. That portion of the chamber G to the on G, together with the. valve with said chamber G, may be conveniently central and rear portions of the average was moderate.

only after unv ist E which freely communicates capacity than the duct g".

freight train. It may now be assumed that (after the brakes were appied) the release was made and the rise of train pipe pressur As the piston was forced by this rise of train pipe pressure, toward the right, (the train pipe fluid entering the piston chamber by the ducts S and T drawing the valves D and E with it, through the medium of the rod F, the piston G first uncovered the passage M and then the larger passage M-,-the rod H coming into contact with the abutment 15 just before the groove M is uncovered and thus causing the spring N to be compressed so that it will operate to exert a slight back pressure on the piston, and will, when the pressures on the two sides of the piston become approximatly equal, cause the piston to close the large passage l in order to prevent an excessive back flow of 'fluid from the auxiliary reservoir when it is subsequently desired'to apply the brakes. v

As before stated, train pipe fluid cannot pass to the controlling space at the left of the piston throu 'h the duct R, by reason of the chuck valve consequently the only path by which train pipe fluid can enter the controlling space is that formed by the ducts S' and T. Now the spring C isso designed that it Wil. permit of a slight lift of the valve C by. a very slight excess of pressure on its lower side, so that during the motion of the piston towards its release posi ions, practically full train pipe pressure is permitted to act in the controlling space, thus insuringa positive release of the brakes, (the train pipe fluid entering the controlling space through the ducts Sand '1 and the small duct g of the check valve 0). But as soon as the piston uncovers the groove M fluid from the controlling space flows through said groove M so rapidly to the auxiliary reservoir that, because of the very restricted inlet through the duct y the pressure in. the controlling space falls slightly to a value intermediate train pipe pressure and auxiliary reservoir pressure, but under the assume of a moderate rise of tram pipe pressure, the

condition pressure in the controlling space will still be sufficiently in excess of that in the auxiliary reservoir to cause the piston to continue its motion till he large groove M is uncovered thereby, when of course a still further reduction-of pressure in the controlling space will take place, as the duct M is of much greater (At this time the spring C, uhich is short and stifl', prevents the checkvalve C from rising far enough to permit of a free flow of air from the duct S to the duct T as the rise of train pipe pressureis only moderate and thus the valveC acts as an excess pressure valve underthese conditions). On account of this reduction of pressure in the controlling -space, thepresisu'res acting; on the two sides oflth'e piston voir is receiving a supply of compressed air' through the duct 7 from that portion of the chamber G to the right of the piston G and that this portion of the chamber isbeing supplied with compressed air from the controlling space through, the passage M of duct M and that fluid is entering the controlling space from the train pipe through the duct g at a moderate rate. As this is the proper charging rate for average conditions, and as this is the most usual charging position of the mechanism, this rate of recharge may be termed the normal rate.

of the mechanism shown in Fig. 1, the main slide valve D establishes a free communication between the ports I) and d by means of the cavity m, thus permitting a rapid discharge of brake cylinder air from the ducts V and U to the outlet (1 and thence to the atmosphere. Thus it is seen that a moderate rise of train pipe pressure it ill cause the mechanism to provide for both a free release of the brakes and a normal rate of recharge of the auxiliary reservoir.

in the above description, a moderate rate of rise of train pipe pressure has been assumed, but should there be only a very slight rise of train pipe pressure, as is the case toward the rear of very long trains, (that is to say, if the force acting on the piston during its motion toward its release portions is only very slightly in excess of that necessary to overcome the friction of the moving parts) v. hen the piston reaches such a position that it uncovers the end of the passage M the resulting flow of air fromthe controlling space to the auxiliary reservoir will so reduce the pressure in the controlling space that the piston w ill no longer be able to overcome the resistance of the moving parts, and its further motion w ill cease. At this time the ports I) and d w ill be freely connected by the cavity m of the valve D, thus providing for the free exhaust of brake cylinder fluid, but the rate of recharge of the auxiliary reser- Wvoir v ill be slightly less than it would have been if the large groove M had been uncovered by the piston. Consequently, the amount of fluid taken from the train pipe under the given condition of a very slow rise of train pipe pressure, is less than would have been taken had the valve been able to assume its normal recharge and free release position as shown in Fig. 1. A greater amount of fluid will, therefore, continue to flow toward the rear portion of'the train (beyond the point where this valve mechanism may be located) than would otherwise be the case and will thus tend to compensate for the In the position large train pipe volume and, as a result, will provide for a more rapid release of the brakes on the extreme rear end of the train than has heretofore been accomplished. This position may therefore be conveniently termed a c ompensating recharge and free release position.

If after the auxiliary reservoirs at the forward portion of the train have become nearly fully recharged and consequently the pressure near the rear of the train, (where the valve mechanism with the parts in the positions now under consideration are located) begins to build up more rapidly, the valve will be forced from this position (namely, its compensating recharge and free release position) to its normal recharge and free release position, as shown in Fig. 1, thus permitting of a more rapid replenishment of the auxiliary reservoir pressure than would be possible if the mechanism were retained in its compensating recharge and free release position. This movement will result from' the fact that when the rise of train pipe pressure is moderately rapid, the small groove orpassage M is unable to convey fluid rapidly enough from the controlling space to the right hand side of piston G in order to maintain the pressures acting on said piston sufflciently nearly equalized to prevent them from overcoming the friction of the moving .so as to fully 0 en communication between the ducts S an T and thus permit the pas sage of a large volume of train pipe fluid into the chamber G to the left of the piston G.

'1 his w ill result in causing a rapid motion of the piston G to the extreme right, as the ducts M and M cannot convey sufficient fluid around the piston to cause even an approximate equalization of pressure on its twosides, (the check valve 0 being wide open). Consequently the piston G is forced against the right hand end of its chamber, and the valves are carried by it into the positions.

shown in Fig.2 whichmay. be called the restricted recharge and restricted release position of the mechanism for when the parts are in the positions above mentioned, air will be permitted-to flow to the auxiliary reservoir only through the very restricted passage M Thus, although the train pipe-pressure is much higher than that in the auxiliary reservoir, the recharge of the latter will be comparatively slow, thereby preventing for a considerable length of time, an overcharge this restricted recharge and restricted release position as shown in Fig. 2, the cavity m m the valve D'will communicate with the brake cylinder port I) and only a small extension e of said. cavity m will communicate with the exhaust port d. The release of I brake cylinder fluid will thus be restricted or retarded to-a .considerable extent and consequently tend to produce a uniform release of therbrakes throughout the whole train (those toward the'rear of the train having an 4 unrestricted release as previously explained) and thus the severe running out of slack between the cars will be prevented. Assume now that it is desired to make a service application of the brakes and that the mechanism isin anyof the release positions:

The gradual reduction of train pipe pressure (such as is usually made in service applications of automatic brakes) will cause a simultaneous reduction of pressure in the valve chamber R and in the piston chamber G- to the left of the piston G,the air from these chambers passing out freely to the train pipe through the port f, duct R, past check valve R and through the duct S. The flow of fluid from the a rxilia reservoir, through the duct M being restricted, the piston will be forced toward the left. When the piston .is'thus forced toward the left, the duct M will become closed. After taking up the lost motion between the rod F and valve D, the rod ill cause said valve to move with it to theleft and because of pushing (instead of pulling) this valve by the rod F, the graduatmg va ve E will be in the extreme left hand position gwi h reference to the main slide valve D will therefore connect ports h and k byii the cavity-p and will also uncover the uppeli end' of ort Z. The first vmotion of the mainslide va ve D to the left, will disconnect the exhaust cavity m from the brake cylinder port I) and the further movement of t e and h, cavity p, orts it and b and duets U and V to the-bra e cylinder.

. The registration-of the small port I the port a permits ofla slight flow of tram pipe fluid to the brake eylindersin order to assist in transmitting the reductlon of tram pipeipres'sure throughoutthe train and-to yaugmentthe'pressure obtainedin the valve ,1) cause the port I to register with the port a, and subsequently port h admitted through the ort l to the brake cylinders must enter the atter by passing the check valve B, which latter at all times prevents a back flow of air through the duct a 'freservoir will take place much more rapidly than the reduction of pressure in the train pipe if the latter be made through the port I alone; r'consequently as soon as the engineer stops t/he reductionof train pipe pressure by means of his brake valve, the pressure behind the piston G will fall below that in front ofit and said piston will move to therighh- The slight difference of pressures required to cause this motion is merely suflicient to overcome the friction of the piston and the graduating valve, so that when the iston has moved until the left hand shoul or F engages the main slide valve, its further motion will be stopped by this means, because it requires considerably more force to move the main valve than is necessary to move the piston and graduating valve alone. By this means therefore: the mechanism is caused to assume a lap position, the parts being located wit'h'reference to each other and to the seat as shown in Fig. .4. It tie-observed that the graduating valve E has now closed the port Z and disconnected and closed the ports h and k. This osition of the mechanism may be termed he uiek service lap position. If now, a furiihertrain pipe reduotion is made by the engineer, the piston will D again move to the left and first cause ports I:

and h to,be connected by means of the grad uating valve and then uncover port Lmthus permitting a further flow of auxiliaay reservoir air and of train pipe air touthe brake cylinder. The object in connecting the auxiliary reservoir and brake cylinder ports before the port] is opened, is topreventvery slight train pipe reductions, (such as occur from leakage) from causing the venting of train pipe fluid to the brake cylinder, as such venting would only amplify the objectionable results obtained from such undesired reductions of train pipe -pressure-.'

The quickser "'ce.pos1t1onof the mech anism (i. .e., thatabovedescribed and shown in Fig. 3) is the position which willbe assumed when the service'reduction of train pipe pressure is made at afairly slow rate, as is the.

caseon mostfreight and long passenger trains. When, however, the service reduction is made on short trains and is consequently fairly rapid the mechamsm may assume apositioh (as shown in Fig. 5) to the left of its quick servicpufiosition, and which may be termed the 'Inth-is position of the mechamsm, the orts sh 6 ltywill noted that the air-thus c and h and b and kare freely connected but service position.

the port Zhas passed over the port a and consequently will no train ipe fluid to the brake cylinders, which flow under the conditions assumed) is obviously not only unnecessary but undesirable.

the service rate, to such a low degree that the pressure in the brake cylinder has become equal to that in the auxiliary reservoir, a furtherreduction of train pipe pressure will obviously cause the piston G to move the slide valves to the lett of their service positions for (because of the equalization of pressures inthe brake cylinder and auxiliary reservoir) the'pressure'in the auxiliary reservoir cannot dropany lower, as a result of this motion of the parts to the left. Consequently, the motion of the parts will.con

tinue until the port f is closed by the valve D, and thus all further flow of air from the valve chamber R to the train pipe is pre-- vented. The valves will now assume the po sition illustrated in Fig. 7. This position of the mechanism may be termed equalization lap and maintaining position It may be here stated that the rod H is of sufficient length to engage the abutment u in the quick service position of the valve for the purpose of'adding the resistance of the spring N to the motion of the valve in its movement past quick service position toward the emergency position, (which latter will be presently described) as well as to cause the graduating valve to close'portZ except for the small port Z of the main valve (when the pressures become equalized on both sides of the piston) in the equalization lap and emergency lap positions simple and efficient-means for the mainteof the valve D.

it will be observed that on accountof the different distances between the ports inthe valve D and the ports in the seat X, andthe 1 length of the rod H when the port Z in the valve D registers withthe brake cylinder port a, the spring N is ada ted to tend to cause the graduating. valve 4 to close said port Z except for the small port Z in the extension Z of said valve E, in the lap positions of the valves shown in Figs. 7 and 9. Thepurpos'e of this arrangement, is to prevent an excessive flow of train pipe fluid to the brake cylinder at the time of the release. The cooperation of the ports Z and Z thus serve to control the flow offiuid from the controlling space {via chambers G -and R to I the brake cylinder.

Reverting now to the equalization lap and ma1ntainingposition of the mechanmm, as shown 111 Fig. 7, it maybestated that longerpermit a flow of:

in this position, the piston G has not yet moved far enough to open or uncover the ducts or grooves L L During the movement of the valve D to this position, it is clear from the spaces existing between the ports, that the port a was slightly opened; after which the port f and ports 0 and b were closed. During this same movement and at all times, the of fluid from the brake cylinder through port a to the slide valve chamber. The object in is to provide means whereby, in emergencyapplications and incase the brake cylinder pressure'be comes depleted by leakage. atter equalization,

. cylinder can cause piston chamber G at the=lett of the piston,

auxiliary reservoir pressure to force the piston to its extreme' lett handposition simultaneously opening-port. a Wide and per-.. mitting air to flow trom the auxiliary reservoir through the groovesL L ductQ and vport a tothe brake cylinder.

the equalization lap position or any other position-to the left-of the same and consequently the main valve has uncovered the port a; if, after reducing the train pipe pressure sufficiently-to cause the -mechanism to or less than this reduced. pressure be maintained in the train pipe through the medium of' a properly adjusted reducing, valve under the control of the engineer, the brake cylinder pressure cannot drop below the-maintained pressure in the train pipe, as air'i s, under the conditions stated, perie'ctlyir'ee; to

by opening the check valves 0 and B flowing through the ducts S and T-and ports Z, Z and a and ducts V, V and 4E. Thus it will be seen that the mechanism provides a nance of brake cylinder pressure in spite of leakage, and yet in no way interferes with the proper action release is desired,-as under the conditions stated, there is no wayior the air to enter the auxiliary reservoir andconsequently the release may be effected with as much ease as in the case of other triple valves which do also evident that this feature, as embodied with the satisfactory operation of the valve when operated on trains having the ordinary forms of-triple' valves, but will operate in perfect unison with them under all conditions. I

Consider, now that the mechanism is in one of its releasev positions and that the train slightly opening port a before closing port f assume such a position, any pressure equal to flow from the train pipe to the brake cylinder of the mechanism when a notembody a maintenance feature. It is check valve B prevents a flow the low pressure in the brake a flow of air from the past the check valve B, and thus'cause the When the parts ot the mechanism assume in my improved mechanism isentirely auto- -mat1c (as long as thetram pipe pressure is maintained) and that 1t in no way interferes pipe pressure is suddenly reduced in order to cause an emergency application of the brakes. This will, of course, effect a rapid motion of the piston and slide valve to the left, causing them -to pass over their service positions, as the reduction of pressure in the train pipe is so rapid that the ressure behind the piston cannot fall as rapi ly through the service ports, and consequently the parts move rapidl to their extreme left hand posi- 'tions, as in icated in Fig. 8. The ort' is st1l,a's jheport ais opened efore port f 18 closed, a very rapid reduction of pressure now-closed and the port a is wi e open. The orts b, c are also" closed and thecavi'ty' m o valve D-i's resting over port d and .thus exposing a largeportion of the area of the faceofthe valve to atmospheric pressure 7 in order to permit the low pressure above it.

to hold'it to its seat, notwithstanding any tendency that the higher pressure existing in the small port 0 may have to lift it from its seat. As the valve moves beyond its service positions toward that shown in Fig. 7

8, although. allifurther flow of air from in front of the piston to the train pipe is sto pedthe instant that the ort f is closed,

. now occurs from in front of the piston through the port'a and its connecting ducts to the brake cylinder. In fact, the opening of the port a not. only insures the full and provides means for rapid y venting a largerapid motion of the piston and valves to their extreme left hand 'ositions, but also amount of train pipe fluid to the brake'cylinder (train pipe fluid assing by check valve C and through ducts and T and port a to the brake cylinder) in order to assist in transmitting the emergency reduction of train pipe pressure throughout the train and to augment the cylinder pressure.

prevented by the-abutment a.

When the valves reach the positions shown in Fig. 8, the movement of the piston will be over travel of the main slide valve D will be It is also apparent that there will now be a free flow of air from the auxiliary reservoir through the port W, around the iston through the grooves L andthroug the ductQ and port a to the brake-cylindert This flowof auxiliary reservoir air is sufficiently restricted'to permit alarge amount of train pipe fluid to enter the brake cylinders, it being evident, as

previously pointed out that a free path is provided in the emergency position, for

a the passage of train pipe fluid to the cylinder.

' When the pressure in the slide valve cham-,

ber finallytendsto become greater than that in the train pipe, the check valve 0 is closed by its spring and aback flow of air to the train 1pipe is thus prevented, as the port is. o'sed as previously pointed out. W en,

also c the pressures in the auxiliary reservoir and brake cylinder (said pressures now acting on 'may approximately equal, the moving arts will assume the position shown in ig. 9,- which position may be termed emergency lap position. The main valve D is stillin its emergency position, but the piston G and graduating valve E have been moved slightly to the right, thus cutting off the grooves L and L This motion of the piston is caused by the sprin N through the medium of the rod H hen the graduating valve E moves to the emergency lap position shown in Fig. 9, the port a will be closed, except for the restricted assage afforded by the small duct Z insaid valve E.

When it is desired to release the brakes at any time it is evident that the train pipe fluid ass by i the check valve 0 into the chain )ers R and G and thus act upon the piston G and force it at once to its release positions.

Having fully described my invention what I'claim as new and desire to secure by Let'- .ters-Patent, is

1. In a triple valve mechanism, the combination with a casing, a piston therein, valve devices for controlling the application and release of the brakes, the space at one side of said piston constituting a controlling space, and means-forintroducing auxiliary reservoir fluid at the other side of said piston, of means for subjecting the side ofthe piston at which train pipe ressure is introduced, to a pressure intermediate that of train pipe pressure and auxiliary reservoirv pressure.

2. In a tri le valve mechanism, the combination with a casing, a piston therein, valve devices for controlling the application and release of the brakes, the space at one side of said piston constituting a controllingspace, and means for introducing auxiliary reservoir fluid at the other side of said piston,

of a duct for train pipe fluid communicating with the controlling space, and means for restricting the passage of fluid through said duct tothe controlling space.

train pipe fluid communicating with the controlling space, and an'excess-pressure valve in said'duct.

4. In a tri 1e valve mechanism, thecombination wit a casing, a piston therein,

valve devices connected with said piston for controlling the application and release of the brakes, the space at one side of said piston constituting a controlling space, and means for introducing auxiliary reservoir fluid at the other side of said piston, of a duct for pipe fluid communicating with, said controlling space, a check valve in said duct, anda restricted passage for train p e fluid controlled by the movements 01" sa check valve.

5. In a triple valve 1nechanisin,-the combination with a casing, a piston therein, a chamber 'in which said piston is contained, a valve chamber, valve devices connected with the piston and located in said chamber for controlling the application and release of the brakes, the space in the valve chamber and in the piston chamber at one side of the piston constituting a controlling-space, and means for introducing auxiliary reservoir fluid at the other sideoi said piston, of a train ipe duct communicating with the .controling space, an excess-pressure valve in said duct, a second duct connecting the train pipe duct with the valve chamber, .and a check valve in said second duct and preventing passage of fluid from the train pipe duct to the valve chamber.

-6.' In a triple valve mechanism, the-combination with a casing, a piston therein, valve devices connected with said piston-for controlling the application and release of the brakes, the space at one side of said-piston constituting a controlling space, means for introducing auxiliary reservoir fluid at the other side of the piston, and a brake cylinder duct, ofnreans for affording a restricted passage between the controlling space and the brake cylinder duct when the ports are in lap position between the service and emer gency positions of the mechanism.

7. In a triple valve mechanism, the combination was a casing, a piston therein, a main valve and a graduating valve, connec tions between'said valves and the piston, the

space at one side of said piston constituting a controlling space, means for introducing auxiliary reservoir fluid at the other side of said piston, and a brake cylinder duct, of a large port near one end of the main valve and a restricted ort in the graduating valve to register wit 1 said large port when the latter communicates with the brake cylinder duct and the parts are in their lap position be.- tween service and emergency positions of the mechanism.

In testimony whereof, I specification in the presence of two subscribing Witneesses.

' HOWARD M; P; MURPHY. \Vitnesses A. N. MITCHELL, R, S. FERGUSON.

have signed this 

